Reverse shoulder systems and methods

ABSTRACT

Reversed glenoid implants, and related kits and methods, are described that include an anchor member having a proximal head and a baseplate having a distal end with a first aperture sized to accept the proximal head of the anchor member. The proximal head is inserted along an un-threaded length thereof from the distal end into the first aperture, and the anchor member is restrained against axial translation with respect to the baseplate but is permitted to rotate with respect to the baseplate.

INCORPORATION BY REFERENCE TO ANY PRIORITY APPLICATIONS

The present application is a continuation of U.S. application Ser. No.15/474,864, filed Mar. 30, 2017, which is a continuation of U.S.application Ser. No. 14/794,544, now U.S. Pat. No. 9,629,725, filed Jul.8, 2015, which is a continuation-in-part of PCT Application No.PCT/US2014/072442, filed Dec. 26, 2014, which claims the prioritybenefit of U.S. Provisional Application No. 61/923,382, filed Jan. 3,2014. Any and all applications for which a foreign or domestic priorityclaim is identified in the Application Data Sheet as filed with thepresent application are hereby incorporated by reference under 37 C.F.R.§ 1.57.

BACKGROUND OF THE INVENTION Field of the Invention

The systems and methods described herein are directed to orthopedicimplants, for example to reverse shoulder replacement systems andmethods for implantation.

Description of the Related Art

Shoulder replacement surgery involves placing a motion providing deviceat the glenohumeral joint, i.e., the joint interface between the scapulaand the proximal humerus of the arm. See FIG. 1. Reverse shoulderreplacement reverses the curvature of the natural glenoid cavity and theproximal head of the humerus. That is, a convex surface of a glenoidcomponent is positioned on the scapula and a concave surface of ahumeral component is positioned on the proximal humerus.

Some reverse shoulder systems have limitations in connection with thefixation of the glenoid component. In some glenoid component designs, aone-piece construct is provided in which a central threaded postprojects from a baseplate. The threaded post provides fixation to thebone of the scapula, but provides little to no flexibility of the finalpositioning of peripheral features of the baseplate, such as screw ormount holes thereon. Also, the unitary nature of this approach requiresmore inventory to provide a proper mix of baseplate configurations andthreaded post sizes.

Other reverse shoulder systems provide a plate having an integral fixedcentral post and a plurality of screws that are placed through eitherthe post or the plate. These systems are limited in that the length,inner diameter, and configuration of the central post are fixed. Assuch, the size of a screw placed through the central post is predefinedwhich limits the ability to perform revisions (subsequent surgeries onthe patient to replace the system). In a revision surgery the oldimplant must be removed and replaced with a new implant. Commonly asubstantial amount of bone is removed with the old implant and in thiscase larger screws are required to securely fix the new glenoid implantto the scapula.

In currently available systems, specifically unitary systems having anintegral fixed central threaded post, independent rotation is notprovided between the post and the baseplate. For these unitary systemsthe post and the baseplate rotate together when the post is driven intothe bone. With other glenoid implants wherein an anchor member is driventhrough the baseplate and extends from a distal end of the baseplate,axial translation of the baseplate relative to the anchor member is notprevented. For these systems, the baseplate is not secured against axialtranslation until the anchor member is fully engaged in the scapula andpulls the baseplate against the surface of the bone thereby preventingrotation of the baseplate.

SUMMARY OF THE INVENTION

There is a need for new shoulder prosthesis systems that can providemore flexibility and better adaptability to patient anatomies whilemaximizing revision options. When implanting reverse shoulder systems itis desirable to independently attach a baseplate to the scapula andthereafter to independently rotate the baseplate with respect to thescapula such that fixation means in the periphery of the baseplate canbe driven into bone thereunder.

A glenoid implant, according to some embodiments disclosed herein,includes an anchor member and a baseplate. The anchor member has alongitudinal portion configured to be secured to a bone and a proximalhead. The proximal head has a first engaging surface. The baseplate hasa proximal end and a distal end. The distal end of the baseplatecomprises a first aperture sized to accept the proximal head of theanchor member and a second engaging surface. When the proximal head isinserted from the distal end of the baseplate into the first aperture,the first engaging surface couples with the second engaging surface. Insome embodiments, the anchor member is restrained against axialtranslation by this engagement with respect to the baseplate but ispermitted to rotate with respect to the baseplate.

Other embodiments of a glenoid implant may further comprise a lockingstructure configured to apply a force to the anchor member. A glenoidimplant may further comprise a glenosphere configured to be attached tothe baseplate. A glenoid implant may also include one or more perimeteranchors for securing the baseplate to bone.

A method for implanting a glenoid implant, according to some embodimentsdisclosed herein, includes providing an anchor member and a baseplate.The anchor member has a longitudinal portion configured to be secured toa bone and a proximal head. The proximal head has a first engagingsurface. The baseplate has a proximal end and a distal end. The distalend of the baseplate comprises a first aperture sized to accept theproximal head of the anchor member and a second engaging surface. Themethod includes securing the anchor member at least partially to bone.The method further includes, with the proximal head of the anchor memberinserted into the first aperture such that the first engaging surface iscoupled to the second engaging surface, rotating the baseplate relativeto the anchor member to adjust the position of the baseplate withoutadjusting the rotational position of the anchor member. The method mayfurther include securing the baseplate to the bone.

In some embodiments, a method further comprises, prior to securing theanchor member at least partially to bone, inserting the proximal headinto the first aperture to cause the first engaging surface to couplewith the second engaging surface. A method may also comprise applying aforce to the anchor member with a locking member to prevent rotationbetween the anchor member and the baseplate. A method may also compriseengaging a glenosphere to the baseplate. In some embodiments, securingthe baseplate to bone comprises inserting one or more perimeter anchorsthrough one or more openings in the baseplate.

Other embodiments of the invention include additional implants orcomponents of implants, as well as further methods, described herein. Asystem or kit may also be provided according to some embodiments,wherein the system or kit comprises a plurality of anchor membersengageable with one or more baseplates and/or a plurality of baseplatesengageable with one or more anchor members, examples of which aredescribed further herein.

In other embodiments, a glenoid implant for a shoulder prosthesis isformed. The glenoid implant comprises an anchor member and a baseplate.The anchor member has a longitudinal portion configured to be secured toa bone and a proximal head. The proximal head has an external threadedsurface. The baseplate has a proximal end and a distal end. The distalend has a first aperture sized to accept the proximal head of the anchormember. The first aperture has an internal threaded surface and a spacedisposed proximal of the internal threaded surface. When the externalthreaded surface of the proximal head is disposed proximal of theinternal threaded surface of the first aperture, the anchor member isrestrained against axial translation with respect to the baseplate butis rotatable with respect to the anchor member.

In another embodiment, a glenoid implant for a shoulder prosthesis isprovided that includes a baseplate, an internal member, and a screw. Thebaseplate has a proximal end, a distal end, an outer periphery, and anaperture that extends therethrough adjacent to the outer periphery. Theaperture extends from the proximal end to a bone engaging surface. Theinternal member disposed in the baseplate has an internal threadedsurface surrounding the aperture. The screw is configured to be placedthrough the aperture. The screw has an external threaded surface. Afirst number of thread starts disposed on the internal threaded surfaceof the internal member is greater than a second number of thread startsdisposed on the external threaded surface of the screw. The threads ofthe external threaded surface of the anchor member have a constantthread form along the length thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features, aspects and advantages are described belowwith reference to the drawings, which are intended to illustrate but notto limit the inventions. In the drawings, like reference charactersdenote corresponding features consistently throughout similarembodiments. The following is a brief description of each of thedrawings.

FIG. 1 is a schematic view of the human shoulder.

FIG. 2 is a perspective view of a glenoid implant in an assembledconfiguration.

FIG. 3 is an exploded view of the glenoid implant shown in FIG. 2.

FIG. 4 is a cross-sectional side view of the glenoid implant shown inFIG. 2.

FIG. 5 is a side view of a baseplate and an anchor member of a glenoidimplant.

FIG. 6 is a cross-sectional, exploded side view of a baseplate, ananchor member and perimeter anchor members.

FIG. 6A illustrates an embodiment of an anchor retention member.

FIGS. 7A-7E are side views of different embodiments of anchor members,which may be assembled into a kit.

FIG. 8A is a top perspective view of a baseplate.

FIGS. 8B-8E are side views of different embodiments of baseplates.

FIGS. 8F-8G are top views of different embodiments of baseplates.

FIG. 8H is a top perspective view of another embodiment of a baseplate.

FIG. 8I is a side view of a baseplate with a distal portion formed byadditive manufacturing.

FIG. 8J is a side view of a lateralized baseplate formed by additivemanufacturing.

FIG. 8K is a half-wedge baseplate formed by additive manufacturing.

FIG. 8L is a full-wedge baseplate formed by additive manufacturing.

FIG. 9A is a cross-sectional side view of a baseplate with a dualthreaded lumen and an anchor member.

FIG. 9B is a cross-sectional side view of the baseplate of FIG. 9A.

FIG. 9C is a cross-sectional side view of a glenoid implant with abaseplate that has a dual threaded lumen and an anchor member.

FIG. 9D is a cross-sectional side view of the baseplate of the glenoidimplant of FIG. 9C.

FIG. 9E shows a kit of anchor members, including the anchor memberillustrated in FIG. 9C.

FIG. 9F is a side cross-sectional view of an assembly including thebaseplate of FIG. 9D and a peripheral screw.

FIG. 9G is a perspective view of one embodiment of an internal member ofthe baseplate of FIG. 9D.

FIG. 9H is a perspective view of one embodiment of a peripheral screw ofthe glenoid assembly of FIG. 9C.

FIG. 9I is a side cross-sectional view of a proximal portion of theperipheral screw of FIG. 9H partially advanced through the internalmember of FIG. 9G.

FIG. 9J is a side cross-sectional view of the proximal portion of theperipheral screw of FIG. 9H fully advanced through the internal memberof FIG. 9G.

FIG. 10 illustrates an implantation tool and a method of using such atool to implant a portion of a glenoid implant.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

While the present description sets forth specific details of variousembodiments, it will be appreciated that the description is illustrativeonly and should not be construed in any way as limiting. Furthermore,various applications of such embodiments and modifications thereto,which may occur to those who are skilled in the art, are alsoencompassed by the general concepts described herein. Each and everyfeature described herein, and each and every combination of two or moreof such features, is included within the scope of the present inventionprovided that the features included in such a combination are notmutually inconsistent.

FIG. 1 depicts the human shoulder. The glenoid cavity is a portion ofthe shoulder that is located on the scapula. The glenoid cavityarticulates with the head of the humerus to permit motion of theglenohumeral joint. Total shoulder arthroplasty replaces theglenohumeral joint with prosthetic articular surfaces that replicate thenaturally occurring concave and convex surfaces of the body. Typically,in total shoulder arthroplasty, an articular surface replaces thehumeral head and an articular surface replaces cartilage in the glenoidcavity. In a typical reverse total shoulder arthroplasty, a glenoidimplant with a convex spherical head is inserted into the glenoid cavityand a complimentary socket is placed on the humerus. Reverse totalshoulder arthroplasty reverses the naturally occurring ball and socketorientation related to the glenohumeral joint.

FIGS. 2-4 depict a glenoid implant 100, more preferably a reverseglenoid implant, configured to be implanted in the glenoid cavity of apatient in the patient's scapula. The glenoid implant 100 includes ananchor member 104 for anchoring the implant 100 in the scapular glenoid,a baseplate 108, a locking structure 112 configured to deter rotation ofthe anchor member relative to the baseplate, and a glenosphere 116having an articular surface (e.g., a convex, spherical surface). Theglenosphere 116 is configured to couple to a complimentary prostheticdevice anchored to the humerus (not shown, but sometimes referred toherein as the humeral component) in order for the joint replacementimplants to replicate the motion of the human shoulder. The humeralcomponent can take any suitable form such as those disclosed inconnection with FIGS. 18-21 and elsewhere in U.S. provisionalapplication No. 61/719,835, filed Oct. 29, 2012, which is incorporatedby reference herein in its entirety. Suitable humeral components can beconfigured to couple with reverse shoulder joint components, includingthose described in connection with FIGS. 1-9, 27-38, and 39-41 of the'835 application. Suitable humeral components can be configured to adaptto anatomical and reverse shoulder configurations. The glenoid implant100 and the humeral component provide a replacement for the naturalglenohumeral joint.

As used herein, the terms “distal” and “proximal” are used to refer tothe orientation of the glenoid implant as shown in FIGS. 2-4. As shownin FIG. 3, a longitudinal axis 120 of the glenoid implant 100 extendsthrough a central longitudinal axis 124 of anchor member 104 (shown inFIGS. 4 and 6). The glenosphere 116 is towards the proximal end alongthe longitudinal axis 120 and the anchor member 104 is towards thedistal end along the longitudinal axis 120. In other words, an elementis proximal to another element if it is closer to a central aperture 128(shown in FIG. 4) of the glenosphere 116 than the other element, and anelement is distal to another element if it closer to a distal tip 132(shown in FIG. 4) of the anchor member 104 than the other element. Atsome points below, reference may be made to the anatomical location. Inuse when the implant is delivered into a patient's scapula, the distaltip 132 of the anchor member 104 is more medial on the patient, whereasthe articular surface of the glenosphere 116 is more lateral on thepatient.

FIGS. 3 and 4 show that the baseplate 108 is oriented substantiallyperpendicular to the longitudinal axis 120 of the glenoid implant 100.The baseplate 108 is shown coupled to the anchor member 104 in FIGS. 4and 5 and apart from the anchor member 104 in FIG. 6. Referring now toFIG. 5, the baseplate 108 has a proximal end 136 and a distal end 140.The proximal end 136 comprises a proximal surface 144 and the distal end140 comprises a distal surface 148. The proximal surface 144 can besubstantially parallel to the distal surface 148. The baseplate 108 canalso include a bone engaging surface 152. A thickness of the baseplate108 defined between the proximal surface 144 and the bone engagingsurface 152 may correspond to the amount that the baseplate 108 extendsabove a surface of the bone when implanted. The thickness can be in arange between about 2 mm and about 12 mm, e.g., between about 4 mm andabout 9 mm, e.g., about 6 mm. Thicknesses of about 3 mm, 5 mm, 7 mm, 8mm, 10 mm and 11 mm are also contemplated. As discussed further below,FIG. 8J illustrates a modified embodiment of a baseplate 108J where thesurface 144 is lateralized relative to the patient's mid-plane. Alateralized baseplate is one in which when combined with an articularcomponent, the articulating surface is shifted laterally relative to themedical plane of the patient compared to an anatomical position of thearticular surface. In the context of a reverse shoulder, the shiftingcan move the center of rotation of the humerus laterally compared to theposition of the center of rotation prior to intervention. In the contextof an anatomic shoulder prosthesis, the lateralized baseplate maysupport an anatomic articular surface that is shifted laterally relativeto the medial surface compared to the glenoid surface prior tointervention. The bone engaging surface 152 can be substantiallyparallel to the proximal surface 144 and/or the distal surface 148.FIGS. 8K-8L illustrate modified embodiments in which the bone engagingsurface varies, e.g., providing a partial or full wedge shape forreasons discussed below.

The baseplate 108 also has a lateral surface 156 that spans between theproximal surface 144 of the baseplate 108 and the bone engaging surface152 of the baseplate 108. The surface 156 is disposed lateral withregard to the center of the implant 100 and also is disposed lateral ofthe mid-plane of the patient when the implant 100 is applied to thepatient. The lateral surface 156 can have a circular profile when viewedin a cross-section plane extending parallel to the proximal surface 144.The diameter of the circular profile can be between about 20 mm andabout 40 mm, e.g., between about 25 mm and about 35 mm, e.g. about 30mm. In some embodiments, the lateral surface 156 of the baseplate 108 isconfigured to form a portion of a friction lock engagement, such as aMorse taper. In one embodiment, the lateral surface 156 of the baseplate108 is tronconical. The term tronconical, as used herein, refers to ashape or surface that is or is similar to a truncated cone. In someembodiments, the lateral surface 156 is configured with a graduallyincreasing perimeter in a direction from proximal surface 144 toward thebone engaging surface 152.

As illustrated in FIG. 5, in some embodiments, the baseplate 108 caninclude a central protrusion 160 that projects distally from the boneengaging surface 152 to the distal end 140. The central protrusion 160has an outer surface 164 that extends from the bone engaging surface 152to the distal surface 148. Referring now to FIG. 6, the centralprotrusion 160 can include a first aperture 168 which may becylindrical. In some embodiments, the first aperture 168 may include agroove 172 along an inner wall of the first aperture. The baseplate 108can have a second aperture 176 that, in some embodiments, extends fromthe first aperture 168 to the proximal end 136 of the baseplate 108,such that a lumen 180 is formed through the baseplate 108. The secondaperture 176 can include an internally threaded surface 184 as shown. Insome embodiments, the second aperture 176 is smaller in diameter thanthe first aperture 168.

FIG. 6 shows that the baseplate 108 includes a plurality of holes, e.g.,two holes 188, 192 positioned laterally outward of the lumen 180, thatare configured to accept perimeter anchor members 196. The holes 188,192 extend from the proximal end 136 of the baseplate 108 to the boneengaging surface 152 of the baseplate 108. These holes 188, 192 are alsoillustrated in FIG. 8A, which illustrates a perspective view of theproximal end 136 of the baseplate 108 of FIGS. 2-6. As illustrated, thebaseplate 108 may have a circular shape, with a thickness between theproximal surface 144 and the bone engaging surface 152 that is less thana diameter of the proximal surface 136. It will be appreciated that thebaseplate 108 need not be circular, and may have other shapes as well.

Referring to FIGS. 3 and 6, the holes 188, 192 can be defined in part byinternal members 200 that are disposed within recesses 204 in baseplate108. In some embodiments, the internal member 200 is semi-spherical andthe recess 204 is semi-spherical, in order to permit movement of, e.g.,rotation and/or tilting of the internal member 200 with respect to thebaseplate 108. The internal member 200 allows a longitudinal axisextending centrally through the holes 188, 192 (for example longitudinalaxis 208 extending through hole 188 as shown in FIG. 6) to be aimed tosome extent toward a desired anatomical feature. The movement of theinternal member 200 allows the positioning and/or aiming of perimeteranchor members 196 toward a desired location. The longitudinal axis 208extending through the hole 188 can be substantially parallel to alongitudinal axis 212 extending through the second aperture 176 and/orlumen 180, as shown by the orientation of the internal member 200 inpart defining the hole 188 or angled with respect to the longitudinalaxis 212 of the second aperture 176 and/or lumen 180, not shown.

The number and position of the holes 188, 192 depends on many factorsincluding the anatomical structure of the patient, the diameter of theperimeter anchor members 196, and size constraints dictated bydimensions of the baseplate 108. Thus, there may be fewer or greaterholes and perimeter anchors members than illustrated. In someembodiments, perimeter anchor members 196 are inserted through thebaseplate 108 from the proximal end 136 thereof. As shown in FIG. 6, theperimeter anchor member 196 can be inserted in the general direction ofArrow A.

FIG. 6 shows that the anchor member 104 is configured to be attached tothe bone of a patient. The anchor member 104 is generally formed of acylindrical longitudinal portion 216 and a proximal head 220, both ofwhich extend along a longitudinal axis 124 of the anchor member 104. Theanchor member 104 has an external lateral surface 224 which may includea self-tapping threaded surface. Other lateral surfaces of anchormembers are discussed below in connection with FIGS. 7A-7E, 8E, 9A, 9Cand 9E. As used herein, a threaded surface is right-handed when thedriving action is performed with clockwise rotation and left-handed whenthe driving action is performed with counterclockwise rotation. Thethreading of the external lateral surface 224 of the anchor member 104may be right-handed or left-handed. In some embodiments, thelongitudinal portion 216 of the anchor member 104 comprises a distallytapered distal tip 132.

FIG. 6 shows that the proximal head 220 can have a cavity 228 disposedabout the longitudinal axis 124. The cavity 228 extends distally fromthe proximal end of the proximal head 220. In some embodiments, thecavity 228 comprises one or more flat surfaces that are capable ofmating with a driver configured to apply rotational force to drive theanchor member 104 into the bone. For example, the cavity 228 can have ahexagonal cross-section, centered on the longitudinal axis 124,configured to mate with a hexagonal cross-section driver. The proximalhead 220 can comprise a groove 232. In some embodiments, the groove 232is a circumferential groove around an external surface of the proximalhead 220. The proximal head 220 may include an inclined surface 236, thefunction of which is discussed in greater detail below.

Referring to FIGS. 5 and 6, the anchor member 104 and the baseplate 108are coupled in the first aperture 168, which is sized to accept theproximal head 220 of the anchor member 104. In some embodiments, theglenoid implant 100 comprises a member 240, as shown in FIGS. 3, 4 and6, that is sized to fit partly within the groove 232 in the proximalhead 220 and partly within the groove 172 in the baseplate 108. Themember 240 can comprise a c-clip, O-ring or similar protruding devicethat can span at least a portion of the groove 232 in the proximal head220 and at least a portion of the groove 172 in the baseplate 108.Alternatively member 240 may be comprised of elastically deformablebarbs, fingers, or other projections having one end attached to andangled away from either head 220 or baseplate 108 such that theprojections are deformed between head and baseplate when head isinserted into baseplate and such that the unattached end of theprojections elastically expands into groove in head or baseplate. Inthis way, the anchor member 104 is held at a fixed position along thelongitudinal axis 120 of the glenoid implant 100, shown in FIG. 4,relative to the baseplate 108. Preferably the coupling provided by themember 240 does not prevent the relative rotation of the anchor member104 and the baseplate 108. In some embodiments, as shown in FIGS. 4 and6, the member 240 is retained within the groove 172 of the baseplate 108before the proximal head 220 of the anchor member 104 is inserted intothe first aperture 168.

FIG. 6 depicts the anchor member 104 separate from the baseplate 108,e.g., before being coupled to the baseplate. The anchor member 104 canbe inserted from the distal end 140 of the baseplate 108 into the firstaperture 168. During insertion, the inclined surface 236 of the proximalhead 220 initially contacts the member 240. Further insertion of theanchor member 104 displaces the member 240 away from the axis 124,farther into the groove 172. Such displacement allows the anchor member104 to be inserted farther into the first aperture 168. The anchormember 104 is inserted into the first aperture 168 until the member 240engages the groove 232 in the proximal head 220. The anchor member 104is retained in the baseplate 108 by the spanning of the member 240across the gap between the longitudinally adjacent grooves 232, 172, asshown in FIG. 4.

In some embodiments, the member 240 is deformed by the proximal head 220when the proximal head 220 is inserted into the first aperture 168. Forexample, the inclined surface 236 can provide a progressively largerforce on the member 240 as the proximal head 220 is urged from thedistal end 140 of the baseplate 108 proximally into the first aperture168 of the central protrusion 160. The inclined surface 236 can have anangle of about 45 degrees or greater. In this context, the angle ismeasured relative to the flattened proximal end of the proximal head220. In one embodiment, the member 240 has a corresponding inclinedsurface 368 (see FIG. 6) that faces distally. When the groove 232 in theproximal head 220 aligns with the groove 172 in the baseplate 108, themember 240 returns to a relaxed state, e.g., is no longer deformed andthe member 240 functions to couple the anchor member 104 to thebaseplate 108. More specifically, the member 240 couples the proximalhead 220 to the first aperture 168.

FIG. 6A illustrates a member 240A having mating ends. In particular, theclip member 240A has a first end 241, a second end 242, and an arcuatesegment 243 therebetween. The inclined surface 368 is provided along adistal-facing side of the arcuate segment 243. The first and second ends241, 242 are configured to mate or nest together when urged toward eachother. For example, the first end 241 can have a reduced thickness onthe distal facing side thereof and the second end 242 can have a reducedthickness on a proximal facing side thereof. The reductions in thicknessof the first and second ends 241, 242 can sum to the total thickness ofthe arcuate segment 243 or more in various embodiment. As a result, theends 241, 242 can move from a spaced apart configuration to anoverlapping configuration with minimal to no deflection of the ends 241,242 in a proximal-distal direction being required. Alternatively, thereductions in thickness of the first and second ends 241, 242 can sum toless than total thickness of the arcuate segment 243. In suchembodiments, upon causing the ends 241, 242 to overlap, deflection ofthe ends along the proximal-distal direction will occur causing awidening of the clip 240A in the region of the ends 241, 242 compared toin the arcuate segment 243. FIG. 6A illustrates an enlargedconfiguration of the member 240A, e.g., a configuration in which ananchor member is being inserted and the clip member 240A is enlarged topermit advancement of a head of the anchor member through the clipmember 240A and a corresponding baseplate. These structures are examplesof various means for preventing axial translation of the baseplate 108relative to the anchor member 104 while permitting rotationtherebetween.

FIG. 4 shows that the glenosphere 116 defines a convex, articularsurface 244. The glenosphere 116 defines an interior surface 248configured to receive the baseplate 108. In particular, the interiorsurface 248 of the glenosphere 116 is configured to couple with thelateral surface 156 of the baseplate 108. In some embodiments, theinterior surface 248 of the glenosphere 116 is configured tofrictionally engage the surface 156, e.g., in a Morse taper. In someembodiments, the interior surface 248 of the glenosphere 116 istronconical. The glenosphere 116 can include an internal threadedsurface 252. In some embodiments, the glenosphere 116 comprises acreep-resistant material, such as a suitable metal including any ofstainless steel, cobalt-chrome alloy, or titanium which permits theinterior surface 248 to deflect slightly in connection with forming asecure connection such as a Morse taper.

Referring to FIGS. 3 and 4, the locking structure 112 can include alocking screw 256, a compression washer 260, and a threaded member 264,which may be a bushing. The locking screw 256 has a body that extendsalong the longitudinal axis 120 when the assembly 100 is assembled. Thelocking screw 256 can have an external threaded surface 272 and aproximal head 276, as shown in FIG. 4. A lateral surface 280 of thelocking screw 256 located between the external threaded surface 272 andthe proximal head 276 has a smooth surface, e.g., one that is notthreaded. In some embodiments, a driver can be introduced into theproximal head 276 of the locking screw 256 in order to rotate thelocking screw 256. The compression washer 260 is generally annular inshape in one embodiment. The threaded member 264 includes one or moreinternal threads 284 configured to mate with the external threadedsurface 272 of the locking screw 256. The threaded member 264 caninclude a sidewall 288 that forms an internal cavity 292 configured tohouse the compression washer 260. The sidewall 288 can have an externalthreaded surface 296 that is configured to mate with an internalthreaded surface 252 of the glenosphere 116. The glenoid implant 100 isconfigured to be assembled as shown in FIGS. 2 and 4.

FIG. 4 shows that during assembly of the locking structure 112, thecompression washer 260 can be inserted into the internal cavity 292 ofthe threaded member 264 and housed within the sidewall 288. The lockingscrew 256 can be inserted through the compression washer 260 from theproximal end to the distal end thereof. A portion of the externalthreaded surface 272 of the locking screw 256 passes through the centralaperture of the compression washer 260. The locking screw 256 can beinserted into the threaded member 264 such that the external threadedsurface 272 of the locking screw 256 mates with the internal thread(s)284 of the threaded member 264. The locking screw 256 can be furtherrotated until the compression washer 260 is loosely retained between thethreaded member 264 and the proximal head 276 of the locking screw 256.The smooth lateral surface 280 can be disposed within the internalthreads 284 of the threaded member 264, when the compression washer 260is loosely retained.

The locking structure 112, which can include the locking screw 256, thecompression washer 260, and the threaded member 264, can be coupled tothe glenosphere 116, as shown in FIG. 4. In some embodiments, thelocking structure 112 is coupled to the glenosphere 116 after thelocking structure 112 has been assembled, as described above. Thethreads on external surface 296 of the sidewall 288 of the threadedmember 264 can be rotated to engage the internal threaded surface 252 ofthe glenosphere 116. This may involve rotation of the locking screw 256toward the threaded member 264, so that the proximal head 276 of thelocking screw 256 fits within the glenosphere 116. The glenosphere 116can have a central aperture 128 that allows access to the proximal head276 of the locking screw 256. The central aperture 128 permits a driveror other tool to engage the locking screw 256. As shown in FIG. 4, theproximal head 276 of the locking screw 256 can have a cavity with one ormore flats, e.g., a hexagonal cavity, configured to mate with thedriver.

The locking structure 112 can be coupled to the baseplate 108, as shownin FIG. 4. In some embodiments, the locking structure 112 is coupled tothe baseplate 108 after the locking structure 112 has been assembled, asdescribed above. In some embodiments, the locking structure 112 iscoupled to the baseplate 108 after the locking structure 112 is coupledto the glenosphere 116, as described above. The locking screw 256 can berotated until the external threaded surface 272 of the locking screw 256engages the second aperture 176 in baseplate 108, in particular thethreaded surface 184 (See FIG. 6). When the locking screw 256 isrotated, the locking screw 256 traverses the second aperture 176distally toward the anchor member 104. Further rotation of the lockingscrew 256 brings the distal tip 300 of the locking screw 256 intocontact with the proximal head 220 of the anchor member 104. In someembodiments, the distal tip 300 of the locking screw 256 enters thecavity 228. The locking screw 256 is capable of applying a force to theproximal head 220 of the anchor member 104. In some embodiments, thisdownward (e.g., distally directed) force applies a compression force tothe member 240 such that the member 240 applies a frictional force tothe groove 232 on the proximal head 220. A friction force will also beapplied by the distal tip 300 to the wall at the distal end of thecavity 228. The distally directed forces created by the locking screw256 on the anchor member 104 and/or the member 240 are sufficient toreduce or prohibit the rotation of the anchor member 104 with respect tothe baseplate 108. For example, high friction can arise due to the highnormal force generated by action of the locking screw 256.

Referring to FIG. 4, when the locking screw 256 is rotated and advancedtowards the anchor member 104, the locking screw 256 can cause a forceto be applied to the glenosphere 116. Rotation of the locking screw 256can move the proximal head 276 toward the distal end of the threadedmember 264. Rotation of the locking screw 256 can bring the proximalhead 276 of the locking screw 256 into contact with the compressionwasher 260. In some embodiments, the proximal head 276 of the lockingscrew 256 can apply a downward force on the compression washer 260. Thecompression washer 260 can thereby apply a downward force on thethreaded member 264. The threaded member 264 including the sidewall 288can be coupled with the internal threaded surface 252 of the glenosphere116. The threaded member 264 can provide a downward force on theglenosphere 116, as the locking screw 256 is advanced distally towardthe anchor member 104. This causes the glenosphere 116 to move distallyand engage the lateral surface 156 of the baseplate 108.

FIG. 4 shows that the lateral surface 156 of the baseplate 108 istapered, e.g., tronconical, in some embodiments. The glenosphere 116defines an interior surface 248 that is tapered or tronconical orotherwise configured to create high friction with the baseplate 108. Thesurfaces 156, 248 can be initially engaged in any suitable manner, e.g.,using an impactor to create an initial frictional engagementtherebetween. In some embodiments, the lateral surface 156 of thebaseplate 108 and the interior surface 248 of the glenosphere 116 form aMorse taper. The distally directed force of the locking screw 256enhances, e.g., makes more rigid, the connection between the anchor 104and baseplate 108, reducing or eliminating play between thesecomponents. As a secondary advantageous effect, the distally directedforce of the locking screw 256 can also increase the friction at thesurfaces 156, 248. The frictional force created by the coupling of theglenosphere 116 and the baseplate 108 add to the rigidity of the glenoidimplant 100.

The compression washer 260 shown in FIG. 4 can have multiple functions.The compression washer 260 is configured to fill the space between theproximal head 276 of the locking screw 256 and the threaded member 264to add to the rigidity of the implant 100. In particular, rotation ofthe locking screw 256 applies a force on the compression washer 260which can compress or otherwise deform the compression washer 260. Inthe compressed state, the compression washer 260 applies a force tomaintain the position of the locking screw 256. The placement and use ofthe compression washer 260 facilitates the rigidity of the glenoidimplant 100 by filling the space between the proximal head 276 of thelocking screw 256 and the threaded member 264. Additionally, the lockingscrew 256 applies a force to the anchor member 104. This force enhancesthe connection of the anchor member 104 to the baseplate 104 whichreduces or eliminate play between these components to minimize or reduceloosening of these components over time. For example, maintaining theposition of the locking screw 256, the compression washer 260 furtherminimizes or prevents rotation, translation, or micromotion of theanchor member 104 with respect to the baseplate 108. In someembodiments, the compression washer 260 tends to distribute the force ofthe proximal head 276 of the locking screw 256. The compression washer260 causes the proximal head 276 of the locking screw 256 to be incontact with a larger surface area of the threaded member 264. Thedistribution of force facilitates the downward movement of theglenosphere 116 with respect to the baseplate 108 and/or enhancesfriction between the surfaces 156, 248 as discussed above. Thecompression washer 260 further minimizes or prevents rotation,translation, or micromotion of the glenosphere 116 with respect to thebaseplate 108.

The glenoid implant 100 can have a modular design, meaning that theanchor member 104 and the baseplate 108 can be interchangeable withanother anchor member and/or another baseplate. In some embodiments asingle baseplate can couple with any one of a plurality of anchormembers in a kit including a plurality of anchor members, such as shownin FIGS. 7A-7E. In some embodiments, a single anchor member can couplewith any one of a plurality of baseplates in some or in another kit,including for example the baseplates shown in FIGS. 8A-8G. The proximalheads of the anchor members can have a consistent diameter among aplurality of anchor members in some kits. Further, the grooves and thecavities of the anchor members can be consistent in size and locationamong a plurality of anchor members in some kits. In some embodiments,the grooves and first apertures of the baseplates is a consistentdiameter among a plurality of baseplates in the kit. Further, the secondapertures and the lumens of the baseplates can be consistent in size andlocation among a plurality of baseplates. This allows for theinterchangeability of the plurality of anchor members with any one of aplurality of baseplates or the plurality of baseplates with any one of aplurality of anchor members.

FIGS. 7A-7E show that the modular design allows the use of a pluralityof anchor members with a given baseplate. In FIGS. 7A-7E, the anchormembers 104A-104E include a longitudinal portion 216A, 216B, 216C, 216Dor 216E, a distal end, a proximal head 220, and a groove 232. The anchormembers 104A-104E shown in FIGS. 7A-7E are compatible with thebaseplates 108, described herein. The anchor members 104A-104E mayinclude additional features of anchor members described herein.

FIGS. 7A-7C differ with respect to the external lateral surface and thelongitudinal portion of the anchor member. The anchor members 104A,104B, 104C may have a longitudinal portion 216A, 216B, 216C havingdifferent configurations, e.g., diameters and/or lengths. Thelongitudinal portion 216A of anchor member 104A has a constant diameterand thread pitch, but different lengths in different embodiments. Theanchor member 104B has a different diameter and/or thread pitch from theanchor member 104A. The anchor member 104C has a different diameterand/or thread pitch from the anchor members 104A and 104B.

As shown in FIGS. 7A-7C, the anchor members 104A-104C can have adifferent diameter in the longitudinal portions 216A-216C. In someembodiments, the diameters are in the range of 6.5 mm to 9.5 mm. Largerdiameter anchor members can be useful for revision of total shoulderarthroplasty or failed reverse shoulder arthroplasty. The anchor membersof the plurality of anchor members can have different lengths, and insome embodiments the lengths of the anchor member can be in the range of15 mm to 40 mm. The external lateral surface is configured to engage abony surface. The configurations shown in FIGS. 7A-7C demonstrate theability to provide, e.g., in a kit, a plurality of anchor members fromwhich a particular anchor member can be selected based on the anatomy ofa patient.

FIG. 7D depicts another embodiment of an anchor member 104D. The anchormember 104D has a cylindrical section of material along the longitudinalportion 216D of the anchor member 104D. The cylindrical section includesporous material 304 to promote bony ingrowth. That is, bone material cangrow into the pores of the cylindrical section of porous material 304.The longitudinal portion 216D may include an external threaded surfaceto engage bone. FIGS. 7A-7D show the proximal head 220 of the anchormembers 104A-104D may have a consistent configuration. For example, theproximal head can have a unitary diameter among a plurality of anchormembers. The anchor member may include a groove that engages member 240as described above.

FIG. 7E shows an anchor member 104E. The longitudinal portion 216E caninclude an external lateral surface that is generally without threads tobe tapped or otherwise pressed into the bone. The external lateralsurface may be comprised of ridges, circumferential ridges, roughcoatings, knurling, plasma sprayed metal, or other rough surfaces thatwill increase the friction of the longitudinal portion 216E relative tothe bone thereby helping to prevent longitudinal portion 216E frompulling out of the bone. The anchor member 104E comprises a proximalhead 220 that is the same as the proximal heads in the anchor members ofFIGS. 7A-7D. The longitudinal portion 216E can be tapered, e.g., havinga narrower transverse profile adjacent to its distal end and a widertransverse profile adjacent to the head 220. The proximal head 220 has agroove 232 that couples with the baseplate 108 in the same manner as theother anchor members discussed herein. The anchor member 104E providesadditional options for the interchangeable anchor member.

The anchor members 104, 104A-104E (described above) and 312 (describedbelow in connection with FIG. 9A) can be made from a biocompatiblematerial such as a metal alloy, polymer, or ceramic. For example, anchormembers can be made from stainless steel, titanium, titanium alloy,cobalt-chrome alloy, and/or PEEK. In some embodiments, the anchor member104, 104A-104E, 312 is more rigid than the baseplate 108. The rigidityof the anchor member 104, 104A-104E, 312 prevents deformation of theanchor member during insertion into the bone and during use as a glenoidimplant.

FIGS. 8A-8L illustrate embodiments of baseplates having features similarto those described above and/or additional features. One or more ofthese features may be interchanged or incorporated into any of thebaseplates described herein. In the embodiment of FIGS. 8A, G and H, onthe proximal surface 144, the baseplate 108, 108G, 108H is illustratedwith tool engaging grooves or openings 398. The tool engaging grooves398 are configured to engage two radially extending legs of a tooldescribed below with reference to FIG. 10. The grooves 398 can bepresent on any of the embodiments of the baseplate described herein.

As shown in the embodiments of FIGS. 5, 8A-8C and 8F-8H, the centralprotrusion 160 is centrally disposed relative to the lateral surface 156of the baseplate 108. For example, a central longitudinal axis of thecentral protrusion 160 can be disposed equidistant from points along thelateral surface 156, as shown in FIG. 5. FIGS. 8B-8L illustrate morefeatures of baseplates that can be combined with and/or substituted forfeatures illustrated in the embodiment of FIGS. 5 and 8A. For example,FIGS. 8B-8E illustrate baseplates 108B-108D with configurations that canaugment or compensate for scapula bone loss. FIG. 8B shows that thebaseplate 108B has a proximal surface 144B. FIG. 8B shows that the boneengaging surface 320 has a curved surface (e.g., a convex surface). Thebone engaging surface 320 is symmetrical with respect to the centralprotrusion. FIG. 8C shows that the bone engaging surface 324 of thebaseplate 108C has an anatomically curved surface. The curved surfacecan be nonsymmetrical with respect to the central protrusion. The curvedsurface can be selected by the surgeon to match an anatomic feature ofthe patient's bone. The bone engaging surfaces 152, 320, 324 can matchthe curvature of the glenoid cavity of the patient.

FIGS. 8J-K illustrate further baseplates 108J-108K that can compensatefor bone loss, thereby augmenting the bone at the joint. The baseplate108J has a proximal portion 136J and a distal portion 140J. The proximalportion 136J can incorporate any of the features or components of theproximal end 136 of the baseplate 108 of FIGS. 2-6, 8A, and 10 or ofproximal ends of other baseplates herein. The distal portion 140J isformed by a process of additive manufacturing, which is discussed below.The additive manufacturing process creates a porous titanium structureon the distal surface of the baseplate. In particular, the distalsurface 148J and central protrusion 160J comprise the porous titaniumstructure described herein. The distal surface 148J can be a surfacethat extends radially outward from the central protrusion 160J andengages an exposed face of the glenoid. The central protrusion 160J canbe configured to be advanced into the bone distal of the bone surfacecontacted by the distal surface 148J. The porous titanium structure canbe disposed throughout the distal portion 140J, which contact thescapula at the glenoid surface. Any technique can be used to form theentirely of the distal portions of the baseplates herein, includingadditive manufacturing. Additive manufacturing can be used to provide aporous titanium structure in the entirety of the distal portions of thebaseplates, including the central protrusions. This approach can providea monolithic portion, e.g., where the same porous structure extendsthrough the entire thickness of the monolithic portion of the baseplate.

The baseplate 108J also includes an augment portion 150J. The augmentportion 150J is configured to move a proximal surface 144J of thebaseplate 108J to a selected location and/or to replace or in-fill areasof bone loss with or without a lateral shifting of the center ofrotation of the humerus at the shoulder joint. For example, thebaseplate 108J may be applied to the patient by attaching it to theglenoid region of the scapula. In certain patients, wear of the glenoidmay be substantially uniform. Uniform wear causes the pre-implantationglenoid surface to be shifted medially compared to an un-worn and/orun-diseased position of the glenoid surface. In such patients, theaugment portion 150J shifts the location of baseplate 108J and therebythe articulating surface of a glenosphere coupled with the baseplate1081. The baseplate 108J shifts the position of the glenospherelaterally. The position of the surface 144J of the lateralized baseplate108J would be more lateral compared to the position of the same surfaceof the baseplate 1081 that would result if the baseplate 1081 were used.That is the surface 144J would be farther from the medial plane of thebody than would be the surface 1441 on the same patient with the sameglenoid condition.

FIG. 8K shows a baseplate 108K that is similar to the baseplate 108Jexcept as described differently below. The baseplate 108K has an augmentportion 150K that is non-uniform in thickness. The augment portion 150Kcan be formed in any suitable way, for example by additive manufacturingproducing a porous metal structure. The augment portion 150K presents afirst thickness, t1, along one peripheral side of the baseplate 108K anda second thickness, t2, along a second peripheral side of the baseplate.The second thickness is larger than the first thickness. The secondthickness can be provided by progressively thickening the augmentportion 150K in a lateral direction (e.g., toward the left in FIG. 8K).In the illustrated embodiment, the thickness of the augment portion 150Klinearly increases across the width of the baseplate 108K. In theillustrated embodiment, a distal surface 148K is provided that engagesthe surface of the scapula, e.g., at the glenoid. The surface 148K has afirst peripheral portion 146K that is parallel to a proximal surface144K of the baseplate 108K. The surface 148K has a second peripheralportion 149K that is disposed at an angle relative to the proximalsurface 144K. The angle between the second peripheral portion 149K andthe proximal surface 144K can be selected based on the amount of bone tobe replaced or supplemented by the augment portion 150K. The firstperipheral portion 146K of the surface 148K can be located closer to theproximal surface 144K than is the second peripheral portion 149K of thesurface 148K. The augment portion 150K provides a partial wedge, e.g., ahalf-wedge configuration. The augment portion 150K is for augmentingbone degeneration and/or disease in the location beneath a glenoidimplant including the baseplate 108K. Although the embodiment of FIG. 8Jcould be used where uneven wear or disease is provided, the baseplate108K can be advantageously used in a bone preserving manner such thatthe un- or less worn portions which would be disposed beneath the firstperipheral portion and the less-thick region of the second peripheralportion need not be reamed or otherwise removed to accommodate thebaseplate 108K. In various embodiments, the entire distal portion of thebaseplate 108K can be made of a porous structure, e.g., of a poroustitanium structure, as discussed herein. The porous titanium structurecan be formed by additive manufacturing. The augment portion 150K can bemade of a porous structure, e.g., of titanium formed by additivemanufacturing.

FIG. 8L shows a baseplate 108L that is similar to the baseplate 108Kexcept as described differently below. In the baseplate 108L an augmentportion 150L is provided that augments bone loss across the entireglenoid surface. In the half-wedge embodiment of FIG. 8K, the angledportion 149K starts or ends inward of the outer periphery of thebaseplate 108K. For example, the angled portion 149K can start adjacentto or at the central protrusion 160K. In the full wedge configuration ofthe baseplate 108L of FIG. 8L, the angled portion 149L starts or ends ator adjacent to a peripheral portion of the baseplate 108L and starts orends at the second peripheral portion, augment extends the full lengthof the implant The baseplate 108L has an augment portion 150L that isnon-uniform in thickness. The augment portion 150L can be formed in anysuitable way, for example by additive manufacturing producing a poroustitanium structure. The augment portion 150L presents a first thickness,T1, along one peripheral side of the baseplate 108L and a secondthickness, T2, along a second peripheral side of the baseplate. Thesecond thickness T2 progressively, e.g., linearly, decreases compared tothe first thickness T1 in one embodiment across the width of thebaseplate 108L. In the illustrated embodiment, a distal surface 148L isprovided that engages the surface of the scapula, e.g., at the glenoid.The surface 148L has a first peripheral portion 149L that is parallel toa proximal surface 144L of the baseplate 108L. The surface 148L has asecond peripheral portion 145L that is disposed at an angle relative tothe proximal surface 144L. The angle between the second portion and theproximal surface 144L can be selected based on the amount of bone to bereplaced or supplemented by the augment portion 150L. The firstperipheral portion of the surface 148L can be located farther from theproximal surface 144L than is the second peripheral portion of thesurface 148L. The augment portion 150L provides a full-wedgeconfiguration. The augment portion 150L is for augmenting bonedegeneration or disease in the location beneath a glenoid implantincluding the baseplate 108L. Although the embodiment of FIG. 8L couldbe used where uneven wear or disease is provided, the baseplate 108L canbe advantageously used in a bone preserving manner such that the un- orless worn portions which would be disposed beneath the less-thick regionof the second peripheral portion need not be reamed or otherwise removedto accommodate the baseplate 108L.

Among the advantages provided by using additive manufacturing to form anaugment portion, such as the augment portion 150J, the augment portion150K or the augment portion 150L is that the augment portion can be madepatient specific in a fast and cost effective manner. For an individualpatient, the need to replace or in-fill bone loss can be determined,such as by pre-operative imaging. The augment portion can be formed inaccordance with this determination. In other words, the augment portioncan be made to replace the lost bone, as determined pre-operatively,when fully integrated into the joint space, e.g., into the scapula orglenoid. This way the fit of the joint can be more accurate for anindividual patient, which can lead to better outcomes such as byreducing the chance of post-operative patient discomfort and jointdislocation.

FIGS. 8D-8E illustrate that the protrusion 328 can be eccentric withrespect to the baseplate 108D. In each of these embodiments, theprotrusion 328 is not centrally disposed relative to the lateral surface156 of the baseplate 108D. An anchor member such as anchor member 104can be inserted into the protrusion 328, as discussed above withreference to central protrusion 160. When an anchor member is coupled tothe baseplate 108D, the anchor member is eccentric with respect to thebaseplate 108D.

FIGS. 8F-8H each illustrate embodiments of a baseplate 108F, 108G, 108Hwith a plurality of holes, e.g., five, holes 190 or four holes 194. Theholes are located around the periphery of the lumen 180. In someembodiments, the holes are equidistant with respect to each other, inother words, the holes are equally spaced around the lumen 180. FIG. 8Gfurther illustrates that tool engaging grooves 398 may also be providedbetween holes 194.

FIG. 8H illustrates a baseplate 108H that has further features that canbe combined with any of the other baseplates herein. The baseplate 108Hhas a radial protrusion 330 disposed between the proximal surface 144and the bone engaging surface (not shown but opposite the surface 144).The radial protrusion 330 has a proximally oriented face 334. The face334 can include an annular surface extending outward from a distalportion of the peripheral surface 156. In one embodiment, the face 334abuts the glenosphere 116 when the glenoid implant 100 is fullyassembled. The radial protrusion 330 can also define a positive stop forthe distal advancement of the glenosphere 116 during assembly of theglenoid implant 100 such that the glenosphere is not overstressed bybeing advanced too far over the surface 156.

In embodiments, such as those illustrated in FIGS. 8I-8L, the baseplatesare at least partially formed by additive manufacturing. In certainadditive manufacturing techniques a material is applied to create athree dimensional porous metal structure. FIG. 8I shows a baseplate 1081that has a proximal end 1361 and a distal end 1401. The proximal end1361 can incorporate any of the features or components of the proximalend 136 of the baseplate 108 or of proximal ends of other baseplatesherein. The distal end 1401 is formed by a process of additivemanufacturing. More specifically, the portion of the baseplate thatinteracts with the bone may comprise a porous metal such as poroustitanium (Ti-6Al-4V). As a result, the distal portions (e.g., theprotrusion 1461 and corresponding protrusions in other embodimentsand/or the augment portion 150J-L) comprise a monolithic porous titaniumstructure, which contacts the scapula at the glenoid surface. Poroustitanium has a modulus similar to bone or of about 2.6 GPa. Matching themodulus of the porous titanium to the bone may enable better stresstransfer from the implant to the bone, reducing wear on the bone, andincreasing strength at the bone/implant interface.

The porous titanium structure includes a pore size of from about 300 toabout 800 μm, in embodiments from about 350 to about 750 μm in furtherembodiments from about 400 to about 700 μm. The porosity of the poroustitanium structure may be optimized per implant geometry and anatomy andcan be of about 50%, 55%, 60%, 65%, 70%, 75%, and 80%.

Porous titanium can be formed by an additive manufacturing process,including a 3 dimensionally (3-D) printing process where layers oftitanium are formed to create a three dimensional structure. The initiallayer or layers are formed by such a method directly onto a portion orsurface of the baseplate. The 3-D printing process includes direct metallaser sintering onto the implant, more specifically, the baseplate.First, blanks are formed by sintering titanium powder with a laserdirectly onto the substrate or baseplate. Next, the blanks can bemachined, constructed or shaped to create a specific geometry of thebone-engaging surface. In another technique, a machined blank isinitially provided. Then, a first layer of a powder form of the materialdesired to make up the formed portion is disposed on and fused to thesurface of the blank. After this, a second layer of the powder isapplied to the part and is fused to the first layer and/or to the blank.This process is repeated to progressively build up the part. Any of thelayers can be full or partial layers to impart complex geometries. Aftera plurality of layers is fused to the blank and to the other layers toform the desired geometry, including an irregular geometry if calledfor, the part can be further processed to eliminate any unfused powder.This process can produce a porous implant well adapted for beingintegrated into bone by bony ingrowth. In embodiments, the blanks areshaped to create either a lateralized (as in FIG. 8J), half-wedge (as inFIG. 8K) or full-wedge (as in FIG. 8L) augmented baseplate. Although the3-D process is used herein to create augmented baseplates, otherportions and surfaces of the implants may comprise porous titanium, andare within the scope of this disclosure, including, but not limited tocentral anchors or screws or portions thereof, peripheral anchors orscrews or portions thereof and central posts. Once constructed, theporous structure and the solid substrate of baseplate comprise amonolithic, or one-piece, structure. Alternatively, Electron BeamMelting (EBM) can be used to 3-D print a porous structure on theimplant.

FIGS. 9A and 9B illustrate an alternative embodiment of an anchor member312 and a baseplate 336. The proximal head 340 of the anchor member 312can include a threaded surface 344, as shown in FIG. 9A. The threadsdisposed on the surface 344 of the proximal head 340 of the anchormember 312 may be left-handed. The first aperture 348 in the baseplate336 can include a threaded surface 352 configured to mate with thethreads on the surface 344 of the proximal head 340. The threadedsurface 352 of the first aperture 348 can be left-handed. Further, thebaseplate 336 can comprise a central portion 356 that is not threaded.The central portion 356 can be surrounded by a smooth surface. Thethreaded surface in the aperture 348 is disposed between the smoothsurface and a distal surface 358 of the baseplate 336. The smoothsurface of the first aperture 348 has a length (e.g., along thelongitudinal axis of the aperture, left to right on FIG. 9B) and a width(e.g., a diameter or dimension transverse to the longitudinal axis ofthe aperture, up and down on FIG. 9B). The threaded surface 344 has alength less than or equal to the length of the smooth surface disposedaround the central portion 356 of the first aperture. When the threadedsurface 344 is housed in the central portion 356, rotation in onedirection does not cause the threaded surface 344 and the threads in theaperture 348 to engage each other in a manner permitting advancementalong the longitudinal axis of the anchor member 312 or the baseplate336. For example, if the threaded surface 344 and the threads in theaperture 348 are left-handed, the baseplate 336 can be rotated clockwisewithout the threads engaging and without the baseplate advancing axiallyalong the longitudinal axis of the anchor member 312. Thus, the anchormember 312 and the baseplate 336 are restrained in axial translation butare permitted to rotate relative to each other. Of course, the threadedsurface 344 and the threads in the aperture 348 could be right-handedand in such arrangement the baseplate could be rotated counterclockwisewithout the threads engaging.

In some embodiments, the anchor member 312 can be advanced from thedistal end 360 of the baseplate 336, through the first aperture 348. Thethreaded surface 344 of the anchor member 312 can engage the threadedsurface 352 of the baseplate 336. The anchor member 312 can be advanceduntil the threaded surface 344 on the proximal head 340 is proximal ofthe threaded surface 352 such that the threads of the surface 344disengage from the threads of the threaded surface 352 of the firstaperture 348. When the threaded surface 344 of the proximal head 340disengages from the threaded surface 352 of the first aperture 348, thethreaded surface 344 of the proximal head 340 is disposed within thecentral portion 356. FIGS. 9A and 9B show that in this configuration,the anchor member 312 is prevented from axial translation with respectto the baseplate 336 but is freely rotatable with respect to thebaseplate 336.

In some embodiments, the proximal head 340 of the anchor member 312 isadvanced into the central portion 356 of the baseplate 336 before theanchor member 312 is driven into the bone. For instance, themanufacturer can provide the anchor member 312 coupled to the baseplate336, as shown in FIG. 9A, or this assembly can be provided by thesurgeon after selecting the baseplate 336 and/or the anchor member 312from a plurality of baseplates and/or anchor members as discussedelsewhere herein. The baseplate 336 can be held in a desired orientationwhen the anchor member 312 is driven into the bone. In some embodiments,the baseplate 336 is maintained in a desired orientation by one or moretools, such as the cannulated tools as described in connection with FIG.10 below while the anchor member 312 is advanced by rotation into thebone.

According to some methods, the anchor member 312 is partially or fullyseated within the bone before the proximal head 340 of the anchor member312 is advanced into the central portion 356 of the baseplate 336. Asnoted above, the first aperture 348 and the threaded surface 344 of theproximal head 340 can have left-handed threads. The external lateralsurface 364 of the anchor member 100 can have right-handed threads. Thebaseplate 336 can be rotated with respect to the proximal head 340 suchthat the proximal head 340 advances through the first aperture 348 andis disposed within the central aperture 356 without disengaging theexternal lateral surface 364 of the anchor member 312 from the bone.Once the threaded surface 344 on the proximal head 340 is containedwithin the central portion 356, the surgeon can then rotate thebaseplate 336 to align the baseplate 336 with anatomical features of thepatient. In some embodiments, following proper orientation of thebaseplate 336 relative to the patient, the surgeon can fully seat anchormember 312 into the bone. In some embodiments, the locking structure112, described in greater detail above, can be utilized with anchormember 312 and baseplate 336. The locking structure 112 applies a forceto the anchor member 312, which prevents subsequent rotation of theanchor member 312 with respect to the baseplate 336. The lockingstructure 112 may also apply a force to glenosphere 116, which creates africtional lock with the baseplate 336. Further details regarding theuse of the locking structure and methods of using the anchor member 312and baseplate 336 are described below.

FIG. 9A shows that the anchor member 312 can be cannulated. Thecannulation allows the anchor member 312 to slide over a guide wireduring insertion. The use of a guide wire helps to ensure the properplacement of the anchor member 312 within the bone. The anchor members104, 104A-104E can also be cannulated to facilitate placement.

FIGS. 9C-9E show an embodiment of a glenoid implant 400 that is similarto the embodiments of FIG. 1 and FIG. 9A except as described differentlybelow. Descriptions of features of the embodiments of FIGS. 1 and 9A-Bmay be combined singly or in combination with the features of FIGS.9C-E. The implant 400 is configured to be implanted in a glenoid of ascapula to provide a portion of a shoulder prosthesis. In certainconfigurations, the implant 400 provides a reverse shoulder componentincluding the glenosphere 116. The glenosphere 116 provides anarticulating surface as discussed above.

FIG. 9C shows that the implant 400 includes an anchor member 404. Theanchor member 404 is shown in FIGS. 9C and 9E and has a longitudinalportion 408 and a proximal head 412. The proximal head 412 has anexternal threaded surface 416. The longitudinal portion 408 and theanchor member 404 are configured to be secured to a bone, e.g., into thescapula at the glenoid. In some embodiments, anchor member 404 can be abone screw component of the implant 400.

FIG. 9E shows that in the anchor member 404 (lower right hand member ofthe kit 399), the proximal head 412 can include a first smooth portion414 disposed distally of the external threaded surface 416 and a secondsmooth portion 417 disposed proximally of the external threaded surface416. When assembled, the proximal smooth portion 417 can extend betweenthe physical proximal end (articulating surface) of anchor member 404and the proximal end of the external threaded surface 416. In somecases, the proximal smooth portion 417 can extend entirely from theproximal end of the anchor member 404 to the external threaded surface416. The distal smooth portion 414 can extend between the externalthreaded surface 416 and threads disposed on the longitudinal portion408. The distal smooth portion 414 can extend entirely from the externalthreaded surface 416 to the threads disposed on the longitudinal portion408. The proximal smooth portion 417 provides an axial insertion zonethat is useful in aligning the threads of the external threaded surface416 with corresponding mating threads of the implant 400 as discussedfurther below. The distal smooth portion 414 is adapted to be alignedwith, e.g., at the same longitudinal position as, threads of a baseplate418 of the implant 400 in a configuration that permits axial restraintof the anchor member 404 while permitting rotational orientation of thebaseplate 418 as discussed further below.

The baseplate 418 that can be similar to any of the baseplates describedherein. FIG. 9D shows an example of the baseplate 418 in more detail.The baseplate 418 can include a proximal end 424 and a distal end 428. Aprotrusion 430 can be disposed on the distal side of the baseplate 418.The protrusion 430 can be a central protrusion or can be locatedperipherally as described herein in connection with certain embodiments.The distal end 428 can include a first aperture 436 sized to accept theproximal head 412 of the anchor member 404. The first aperture 436 cancomprise an internal threaded surface 440 and a smooth surface 444disposed therein. The smooth surface can be located proximal of theinternal threaded surface 440.

The smooth surface 444 is disposed in the central protrusion 430 at alocation immediately adjacent to the threaded surface 440 in oneembodiment. The smooth surface 444 defines a portion that permitsrotational orienting of the baseplate 418 relative to the anchor member404 without axially advancing the baseplate 418 relative to an anchormember. The smooth surface 444 can define a length of the first aperture436 that has a larger diameter than that of the threaded surface 440.The larger diameter section can correspond to a reduced wall thicknessradially outward of the smooth surface 444 in the central protrusion430. In other embodiments, the central protrusion 430 could be thickerin the area of the smooth surface 444 to allow the wall thickness to notdecrease in the area of the smooth surface 444. The length of the smoothsurface 444 preferably is larger than the length of the externalthreaded surface 416 of the proximal head 412 of the anchor member 404.As a result, the external threaded surface 416 can be aligned with,e.g., disposed within the smooth surface 444 in one configuration.

The central protrusion 430 preferably also has an anchor memberinterface zone 448 proximal of the smooth surface 444. The interfacezone 448 surrounds the proximal smooth portion 417 of the anchor member404 in one configuration. The proximal smooth portion 417 can be used toinitially align the anchor member 404 with the baseplate 418. Forexample, the proximal smooth portion 417 can include an unthreadedlength that can have an outer diameter that is less than the innerdiameter of the threads of the internal threaded surface 440 of thebaseplate 418. This permits the unthreaded length of the proximal smoothportion 417 to be inserted into the first aperture 436 and through theinternal threaded surface 440 without any threaded engagement. Theunthreaded engagement allows the surgeon to align the longitudinal axisof the anchor member 404 with the longitudinal axis of the aperture 436or otherwise position the anchor member relative to the baseplate 418 toallow for quick threading of the member 404 to the baseplate 418. Suchalignment facilitates engaging thread-start(s) of the internal threadedsurface 440 with the thread start(s) on the external threaded surface416 of the anchor member 404 without cross-threading these components.In this context, a thread-“start” is a broad term that includes eitherend of a thread regardless of whether the end is initially threaded intoanother structure.

In use, the arrangement of the implant 400 provides for axiallyrestraining the position of the baseplate 418 relative to the anchormember 404. At the same time, the implant 400 permits rotationalpositioning of the baseplate 418 relative to the anchor member 404. Forexample, when the external threaded surface 416 of the proximal head 412is disposed proximal of the internal threaded surface 440 of the firstaperture 436, the threads disposed on these threaded surfaces aredisengaged. In the illustrated arrangement, the external threadedsurface 416 is disposed adjacent to, e.g., in the same longitudinalposition within the aperture 436 as the smooth surface 444 of the firstaperture 436. In this position, the baseplate 418 is axially restrainedbut is configured to allow rotational alignment. In this context, thethreads are said to be in the same longitudinal position along thelongitudinal axis of the aperture 436 when the distal-most aspect of theexternal threaded surface 416 the anchor member 404 is located proximalof a distal end of the smooth surface 444 of the first aperture 436. Insome embodiments, the proximal-most aspect of the external threadedsurface 416 of the anchor member 404 is located distal of the proximalend of the smooth surface 444 when the threaded surface 416 is in thesame longitudinal position as the surface 444. In some configurations,the distal-most aspect of the external threaded surface 416 is proximalof the distal end of the smooth surface 444 and the proximal-most aspectof the external threaded surface 416 is distal of the proximal end ofthe smooth surface 444. When the external threaded surface 416 is in thesame longitudinal position as the smooth surface 444 there is no threadengagement and thus the threads do not result in axially advancement ofthe baseplate 418 relative to the anchor member 404 upon relativerotation.

The baseplate 418 also includes an internal member 460 disposed therein.The internal member 460 is disposed peripherally relative to the firstaperture 436. The internal member 460 is movably mounted in thebaseplate 418. For example, the internal member 460 can have a sphericalouter surface 464 that is mated with a spherical inner surface 468disposed in the baseplate 418. As discussed below, the internal member460 can have various flats or projections as well as an outer surfacethat otherwise generally conforms to a sphere in at least oneembodiment. In other embodiments, the internal member 460 has a curvedsurface that is movable within the baseplate 418 about a range of motionenabling directing peripheral screws (e.g., the peripheral screw 196discussed above in connection with FIG. 6) into the bone. The internalmember 460 can have internal threads 472 that mate with the peripheralscrew. FIGS. 9F-9H, which are discussed below, elaborate on theperipheral screws and internal member 460 provide advantageous featuresdiscussed below.

FIG. 9E also shows a kit 399 that can include the anchor member 404 aswell as anchor members 404A and 404B having different length anddiameter respectively. The anchor member 404A may be well suited forpatients with thinner bone portions beneath the glenoid. The anchormember 404B may be well suited for a revision patient, e.g., a patientbeing adapted from an anatomical shoulder joint to a reverse shoulderjoint, where a pre-existing hole in the scapula can be re-used with alarger diameter screw. In each case, the proximal portion of the anchormember 404A, 404B is adapted for the same engagement with a baseplate asdescribed above. That is the smooth sections 414, 417, where provided,can be received in the baseplate 418 and the threaded portion 416 can bedisposed in the same longitudinal position in the aperture 436 as theportion 444 to permit rotation of the baseplate relative to the anchors404A, 404B which rotation does not cause axial advancement of thebaseplate as in a threaded connection. An anchor member 404C can beprovided with a threadless distal portion. Such an implant can be usedto secure in bone where ingrowth provides sufficient securement to thepatient's bone or where the bone is too brittle to support a threadedanchor member. The anchor member 404C provides the threaded section 416immediately adjacent to the distal portion thereof. As a result, theanchor member 404C is able to secure to any of the baseplates herein byvirtue of the threads 416. When the threads 416 of the anchor member404C are fully engaged with a baseplate, further rotation of thebaseplate relative to the anchor member 404C will be prevented by theproximal face of the threadless longitudinal portion 408C. Furtherrotation of a baseplate will result in rotation of the anchor member404C in the bone. Such further rotation is acceptable because thelongitudinal portion 408C is not threaded and thus is not secured to thebone at this stage of the procedure. The anchor member 404C is suitablewhere less precision is required in rotation alignment of thecorresponding baseplate.

A method of using the glenoid implant 100 can include a plurality ofsteps, in addition to the method of assembling the glenoid implant 100described above. The surgeon may select one or more of the plurality ofsteps. Further, a manufacturer providing a glenoid implant can provideinstructions for one or more of the plurality of steps.

In one embodiment, a method of using a glenoid implant comprisesselecting a preferred baseplate and/or preferred anchor member from aplurality of anchor members such as anchor members 104, 104A-104E, 312and/or a plurality of baseplates such as baseplates 108, 108B-108G, 336described above, to best suit the patient. For example, any of thebaseplates 108, 108B-108G, 336 and/or the anchors 104, 104A-104E, 312can be selected based upon the shape of the prepared bone. Thebaseplates and/or anchors can also be selected based on patient anatomy.For example, a baseplate could be selected that has holes arranged to bepositioned above underlying scapular bone. Or a baseplate could beselected that has holes arranged to be positioned above underlying highquality, e.g., high density, bone. As discussed above with reference toFIGS. 5 and 8A-8G, the baseplate can have a variety of different boneengaging surfaces 152, 316, 320, 324 332, and configurations in order tobest suit the patient. Further, the surgeon may select from a variety ofbone anchors, such as those shown in FIGS. 6, 7A-7E, and 9A-9B. Theplurality of anchor members can include different diameters of thelongitudinal portion, wherein the bone anchor is selected based on thebest fit with the anatomic structure of the patient, specifically thebest fit in accordance with the glenoid that was removed. As notedabove, the bottom loaded design (e.g., where the anchor member isinserted in the distal end 140 of the baseplate) permits thelongitudinal portion and the external lateral surface of the anchormember to have a larger diameter than the diameter of one or more of thefollowing: the second aperture, the first aperture, the lumen, and thecentral protrusion, which is an advantage for revision cases where muchglenoid bone is typically removed. Further, the surgeon can make thisselection after exposing the shoulder joint and inspecting the patient'sanatomy. The bone anchors in the kit can have different thread pitch,lengths and diameters of the longitudinal portion, and integralcomponents such as those to promote bony ingrowth, as shown in FIG. 7D.

After selecting a preferred anchor member and a preferred baseplate, thesurgeon or other practitioner may attach the anchor member to thebaseplate. For example, a surgeon may insert the proximal head 220 ofany of the anchor members 104, 104A-104E into the first aperture 168 ofany of the baseplates 108, 108B-108G. This insertion can result incoupling the anchor member 104, 104A-104E to the baseplate 108,108B-108G. The proximal head 220 is inserted from the distal end 140 ofthe baseplate 108, 108B-108G into the first aperture 168. The proximalhead 220 does not traverse the second aperture 176. The longitudinalportion 216, 216A-216E of the anchor member 104, 104A-104E remainsdistal to the baseplate 108, 108B-108G when the proximal head 220 of theanchor member 104, 104A-104E is inserted into the first aperture 168 ofthe baseplate 108, 108B-108G. The longitudinal portion 216, 216A-216E ofthe anchor member 104, 104A-104E is not inserted into the first aperture168. The longitudinal portion 216, 216A-216E of the anchor member 104,104A-104E is not inserted into the second aperture 176. The longitudinalportion 216, 216A-216E of the anchor member 104, 104A-104E remainsoutside the confines of the baseplate 108, 108B-108G during coupling ofthe anchor member 104, 104A-104E to the baseplate 108, 108B-108G. Duringcoupling, the longitudinal portion 216, 216A-216E extends distally.

As shown in FIG. 10, an anchor member (such as anchor member 104) with abaseplate pre-attached (such as baseplate 108) can be inserted into abone such as the scapular glenoid. It will be appreciated that althoughcertain embodiments described herein involve the surgeon or practitionerpre-attaching the anchor member and baseplate before inserting theanchor member into bone, in other embodiments, the anchor member may beinserted separately from the baseplate. For example, an anchor member104 may be at least partially seated or fully seated within the bonebefore the proximal head 220 of the anchor member 104 is inserted intothe first aperture 168 of the baseplate 108. In yet other embodiments,an anchor member and a baseplate may come pre-attached by themanufacturer.

With reference to FIG. 10, as the surgeon prepares the patient for theimplantation of the glenoid implant 100, the surgeon first pierces ahole in the glenoid, typically the hole being slightly smaller than thediameter of the anchor member 104. In one embodiment, the surgeonrotates the anchor member 104 into the glenoid using a tool designed tomate with the cavity 228 of the anchor member, e.g., with a hexagonaltip. This tool may be inserted through the lumen 180 in the baseplatewhen the baseplate is pre-attached to the anchor member. Theself-tapping threads of the external lateral surface 224 of the anchormember 104, if provided, permit the anchor member to be driven into thebone, optionally into the pre-formed hole. The surgeon can insert aguide wire into the bone in combination with a cannulated anchor member.The guide wire can facilitate placement of the anchor member withrespect to the bone.

In some methods, a hole is made in the glenoid of a diameter of thecentral protrusion 160 of the baseplate 108 in order to accommodate thecentral protrusion 160 when the anchor member is fully seated in thebone. One method step includes shaping the bone to match the distalsurface 148 of the baseplate 108. The hole in the glenoid and theshaping of the bone may be done to accommodate the shapes of any of theother baseplates (e.g., baseplates 108B-108G and 336) described herein.

In certain embodiments the anchor member is pre-attached to thebaseplate. In other embodiments, the anchor member is or can be attachedto the baseplate by the surgeon during implantation.

After advancing the anchor into the bone such that the baseplate isadjacent to the glenoid the anchor member can be rotated (e.g. driveninto the bone) without corresponding rotation of the baseplate. Thesearrangements allow the surgeon to position the baseplate relative tobone, specifically anatomical features of the bone, and maintain thatposition as the bone anchor member is rotated further into the bone tofrictionally secure the baseplate to the bone). In some embodiments, thebaseplate 108 is held in a desired orientation when the anchor member104 is driven into the bone. In some embodiments, the baseplate 108 ismaintained in a desired orientation by tools, as described below.

Referring now to FIG. 10, in some methods tools are used to maintain theorientation of the baseplate 108 relative to the bone. In oneembodiment, a cannula 372 is configured to interact with the baseplate108. In some embodiments, the cannula 372 has two radially extendinglegs 376, 380. The radially extending legs 376, 380 permit the cannula372 to be a smaller diameter than the diameter of the baseplate 108. Insome embodiments, the radially extending legs 376, 380 include a distalfeature that mates with a feature on the proximal end 136 of thebaseplate 108, for instance with tool engaging grooves 398 shown in FIG.8A. In some embodiments, the radially extending legs 376, 380 mayextend, and partially cover the holes 188, 192. In some embodiments, thecannula 372 is sized to accept an inner cannula 384. The inner cannula384 can have multiple functions in some embodiments. The inner cannula384 can be configured to assist in docking and un-docking the legs 376,380 with the baseplate 108. For example, the outer profile of the innercannula 384 can be larger than the inner profile of the outer cannula372 near the distal end of the legs 376, 380. As the inner cannula 384is advanced distally in the outer cannula 372 the outer surface of theinner cannula 384 spreads the legs 376, 380. Another function for theinner cannula 384 in some embodiments is to provide access for a drivertherethrough to mate with the cavity 228 in the proximal head 220 of theanchor member 104. The inner cannula 284 can have an inner lumen toprovide such access. Thus, the driver can be used to insert the anchormember 104 into the bone while the cannula 372 maintains the rotationalorientation of the baseplate 108. The cannula 372 may further be used torotate baseplate 108 to a desired orientation with respect to the bone.

In some embodiments, the baseplate 108 is rotated to align the holes188, 192 (shown in FIG. 6) with anatomic features of the patient. Insome embodiments, the baseplate 108 is rotated to align the boneengaging surface 152 with anatomic features of the patient. When thebaseplate 108 is coupled to the anchor member 104, the baseplate 108 isfreely rotatable with respect to the anchor member 104. The baseplate108 can be rotated and orientated without adjusting the rotationalposition of the anchor member 104. The anchor member 104 can be rotatedand orientated without adjusting the rotational position of thebaseplate 108. In some embodiments, the baseplate 108 is rotated afterthe anchor member 104 is partially or fully driven into the bone. Insome embodiments, the baseplate 108 is rotated before the anchor member104 is driven into the bone.

Following proper orientation of the baseplate 108 relative to the bone,the surgeon can fully seat anchor member 104 into the bone using thedriver. After the anchor member 104 is fully seated in the bone and thebaseplate 108 is properly oriented relative to the bone, or peripheralanchors or screws 196 such as shown in FIG. 6 may be inserted into holes188 and 192 provided in the baseplate 108. In some embodiments,perimeter anchors 196 are inserted from the proximal end 136 of thebaseplate 108 to the bone engaging surface 152 of the baseplate 108, orthrough the baseplate 108. This is the opposite direction the anchormember 104 is inserted into the baseplate 108.

FIGS. 9F-9J show variations of an advantageous peripheral screw assembly484 of the glenoid implant 400. The peripheral screw assembly 484includes the baseplate 418, an internal member 460 and a peripheralscrew 488. The internal member 460 is disposed between an outerperiphery 492 of the baseplate 418 and the central protrusion 430.

FIG. 9F shows an aperture 496 that extends through the baseplate 418adjacent to the outer periphery 492. The aperture 496 extends from aproximal surface 500 of the baseplate 418 to a distal portion 504thereof. The distal portion 504 can be a side of the baseplate 418 thatengages the bone when the baseplate 418 is applied to the patient. InFIG. 9F one of the apertures 496 is labeled and another aperture 496 isshown with a peripheral screw 488 disposed therein, but not labeled forclarity. The internal member 460 is disposed in the aperture 496 of thebaseplate 418. FIG. 9G shows the internal member 460 having an internalthreaded surface 472. The internal threaded surface 472 is disposedwithin the aperture 496.

FIG. 9G shows that in one embodiment, the internal member 460 has aC-shaped configuration including a peripheral wall 512. The peripheralwall 512 extends around a lumen 516. The lumen 516 extends along an axisL. A gap 520 is provided in the wall 512. The gap 520 provides forflexing and movement of the internal member 460 when disposed in thebaseplate 418. The outer surface 520 of the wall is configured to permitrotation of the internal member 460 within the aperture 496. Forexample, the outer surface can be curved and even at least partiallyspherical in some embodiments to move easily in the aperture 496 priorto being secured into a selected orientation as discussed below. Theinternal threaded surface 472 has a thread-start 524 disposed thereon.As discussed above, in this context, a thread-“start” is a broad termthat includes either end of a thread regardless of whether the end isinitially threaded into another structure. In some embodiments, theinternal threaded surface 472 has a plurality of thread-starts 524disposed therein. FIG. 9G shows an embodiment with four thread-starts.Two of the thread-starts 524 are shown in the perspective view and anadditional two thread-starts are disposed on a portion of the wallopposite to the thread-starts that are shown. In other embodiments,there can be six, eight or ten or any other number of thread-starts.

The internal member 460 can have other features disposed on the outsidewall thereof. A protrusion 534 can be disposed on the outside wall toengage a corresponding recess in the aperture 496 of the baseplate. Theprotrusion 534 allows the internal member 460 to rotate but prevents themember from being dislodged from the aperture 496. The internal member460 can have flats 438 disposed on the external wall. The flats make theinternal member 460 more flexible such that it can be deflected to asecured configuration as discussed below.

The peripheral screw assembly 484 includes the peripheral screw 488configured to be placed through the aperture 496. The screw 488 has aproximal end 544, a distal end 548, and a body 550 that extends alongthe length thereof. The proximal end 544 can include a head 548 that hasa tool engagement feature on an end and a tapered portion 552 projectingdistally from the end. The screw 488 has an external threaded surface556. The external threaded surface 556 includes a thread-start 560disposed at the distal end 548. Accordingly, the external threadedsurface 556 includes a thread-start 564 disposed near the proximal end544 adjacent to the tapered portion 552 of the head 548.

FIGS. 9H-9I show that the peripheral screw 488 includes profile with adiameter that is not constant along the length of the body of the screw.The screw 488 has a proximal portion 572 with a larger diameter sectionand a distal portion 576 with a smaller diameter section. The diameterof the screw 488 is enlarged, and may be stepped or changed in diameterin some embodiments adjacent to the proximal end 544 of the screw 488.The screw 488 preferably has the same thread form in the proximalportion 572 and in the distal potion 576. For example, the thread pitchcan be the same in the proximal and distal portions 572, 576. Theconstant thread form in combination with the threading of internalmember 460 enables the screw 488 to be advanced at a constant rate inboth the proximal and distal portions 572, 576.

In one embodiment, the internal member 460 has a first number ofthread-starts 524 disposed on the internal threaded surface 472. Thenumber of thread-starts is greater than the number of thread-starts onthe disposed on the external threaded surface 556 of the anchor member488. This enables the screw 488 to be more rapidly advanced through theinternal member 460. In one embodiment, the glenoid implant 400 isprovided with the internal member 460 having two times the number ofthread-starts 524 as the number of thread-starts 560 on the anchormember 488.

FIG. 9I shows partial advancement of the peripheral screw 488 throughthe internal member 460. In this position, the gap 520 of the member 460is not significantly expanded by the presence of the screw. As a result,the internal member is permitted to move to some extent allowing thetrajectory of the aperture 496 and accordingly the screw 488 to beadjusted relative to the baseplate.

FIG. 9J shows full advancement of the peripheral screw 488 through theinternal member 460. In this position, the proximal portion 572 isdisposed within the internal member 460. The larger diameter of theproximal portion 572 causes the internal member 460 to expand within theaperture 496. When the screw 488 is in this position, the gap 520 isenlarged to an extent sufficient to cause the peripheral wall 512 to beurged into secure engagement with an inside of the baseplate 418. Thesecure engagement can include a high friction force being appliedbetween these walls of the implant 400 such that movement of theaperture 496 is not possible or is minimal. By securing the orientationof the internal member 460 there is less play in the implant 400 makingthe implant less prone loosening after being secured to the scapula.

In some embodiments, after the anchor member and baseplate are attachedto the bone, the locking structure 112 may be used to further secure theanchor member relative to the baseplate and to attach the glenosphere tothe baseplate. For example, after the anchor member 104 shown in FIG. 10has been inserted into the bone, the baseplate 108 is in the desiredorientation with respect to the patient, and the perimeter anchors 196have been inserted, the rotation of the anchor member 104 with respectto the baseplate 108 can be restricted via the locking structure 112.With the locking structure 112 already assembled as described withrespect to FIG. 3 above, and either with or without the glenosphere 116attached to the threaded member 264, the locking screw 256 is insertedinto the second aperture 176 of the baseplate which has the threadedsurface 184. The locking screw 256 is rotated until the locking screw256 applies a force on the proximal head 220 of the anchor member 104.In some embodiments, the locking screw 256 enters a cavity 228 in theproximal head 220 of the anchor member 104. In some embodiments, theforce interacts with the member 240 to prevent rotation of the anchormember 104 with respect to the baseplate 108. After application of forceby the locking screw 256, the anchor member 104 is prohibited from axialtranslation and rotation with respect to the baseplate 108.

With the locking structure 112 in place, a glenosphere 116 such as shownin FIGS. 3 and 4 may be attached to the baseplate 108. In oneembodiment, the glenosphere 116 may have already been attached to thethreaded member 264 when the locking screw 256 is inserted into thecavity 228 in the proximal head 220 of the anchor member 104. In anotherembodiment, the gleno sphere 116 may be attached to threaded member 264after the locking screw 256 is inserted into the cavity 228. In someembodiments, the lateral surface 156 of the baseplate 108 is tapered andthe interior surface 248 of the glenosphere 116 is tapered. When theglenosphere 116 moves distally, the interior surface 248 engages withthe lateral surface 156 of the baseplate 108. In some embodiments, theinterior surface 248 and the lateral surface 156 form a Morse taper.

In some embodiments, the locking screw 256 simultaneously applies aforce to the anchor member 104 and the glenosphere 116 when the lockingscrew 256 is advanced through the second aperture 176. In someembodiments, the glenoid implant 100 is dimensioned so that the lockingscrew 256 applies a force to the proximal head 220 of the anchor member104 simultaneously with the glenosphere 116 interior surface 248 matingwith the lateral surface of the baseplate 108. In this way, the lockingscrew 256 creates a downward force on the anchor member 104 and createsa downward force on the threaded member 264 which is coupled to theglenosphere 116. The downward force causes the interior surface 248 andthe lateral surface 156 to engage. In some embodiments, the lockingscrew 256 creates a push force on the glenosphere 116 and/or a pullforce on the baseplate 108.

As illustrated in FIG. 4, the compression washer 260 provided betweenthe proximal head 276 of the locking screw 256 and the baseplate 108 maybe utilized to prevent micromotion. The compression washer 260 providesresistance against backout when the locking screw 256 creates a pushforce on the anchor member 104. The compression washer 260 is designedto fill the space between the proximal head 276 of the locking screw 256and the threaded member 264 as the locking screw 256 creates a pushforce on the glenosphere 116 and/or pull force on the baseplate 108. Theplacement and use of the compression washer 260 facilitates the rigidityof the glenoid implant 100, and further prevents rotation, translationand/or micromotion of the anchor member 104 with respect to thebaseplate 108. Further, preventing micromotion involves no additionalstep from the current procedure of securing a locking member.

In some embodiments, a bone graft (not shown) may be placed into thebone. The bone graft can be attached to or disposed about any of thesurfaces or portions of the baseplates described herein including thedistal surface 148, distal end 140, the bone engaging surface 152, 316,320, 324, 332, the central protrusion 160, 328, or the longitudinalportion 216, 216A-216E of the anchor member 104, 104A-104E or any otherfeature that would benefit from bony ingrowth. Allowing the anchormember 104, 104A-104E to be driven into the bone independently ofrotation of the baseplate 108, 108B-108G causes less wear and stress onthe bone graft during insertion. In some embodiments, the anchor member104, 104A-104E is freely rotatable with respect to the bone graft. Insome embodiments, the bone graft is coupled to the baseplate 108,108B-108G and rotates when the baseplate 108, 108B-108G rotates but notwhen the anchor member 104, 104A-104E rotates. In some embodiments, thebone graft is inserted after the anchor members 104, 104A-104E is fullyor partially seated within the bone.

Although these inventions have been disclosed in the context of certainpreferred embodiments and examples, it will be understood by thoseskilled in the art that the present inventions extend beyond thespecifically disclosed embodiments to other alternative embodimentsand/or uses of the inventions and obvious modifications and equivalentsthereof. In addition, while several variations of the inventions havebeen shown and described in detail, other modifications, which arewithin the scope of these inventions, will be readily apparent to thoseof skill in the art based upon this disclosure. It is also contemplatedthat various combination or sub-combinations of the specific featuresand aspects of the embodiments may be made and still fall within thescope of the inventions. It should be understood that various featuresand aspects of the disclosed embodiments can be combined with orsubstituted for one another in order to form varying modes of thedisclosed inventions. Thus, it is intended that the scope of at leastsome of the present inventions herein disclosed should not be limited bythe particular disclosed embodiments described above.

1-8. (canceled)
 9. A glenoid implant for a shoulder prosthesiscomprising: an anchor member comprising a longitudinal portionconfigured to be secured to a bone and a proximal head; a baseplatecomprising a proximal portion and a distal portion, the baseplateconfigured to receive the proximal head of the anchor member from thedistal portion of the baseplate; and means for constraining relativemotion of the anchor member and the baseplate, such that when theproximal head and the baseplate are axially connected, axial translationtherebetween is substantially prevented and the anchor member andbaseplate are substantially free to rotate with respect to each other.10. The glenoid implant of claim 9, wherein the means for constrainingrelative motion includes a first engaging surface and a second engagingsurface, the proximal head of the anchor member comprising the firstengaging surface, the distal end of the base plate comprising the secondengaging surface.
 11. The glenoid implant of claim 10, wherein when theproximal head and the baseplate are axially connected, the firstengaging surface is directly coupled to the second engaging surface. 12.The glenoid implant of claim 10, wherein the first engaging surfacecomprises a first groove and the second engaging surface comprises asecond groove.
 13. The glenoid implant of claim 10, wherein the secondengaging surface comprises a smooth region, and wherein when theproximal head and the baseplate are axially connected, the firstengaging surface of the proximal head is disposed within the smoothregion of the second engaging surface.
 14. The glenoid implant of claim10, wherein the first engaging surface comprises threads.
 15. Theglenoid implant of claim 10, wherein the second engaging surfacecomprises threads.
 16. The glenoid implant of claim 10, wherein when theproximal head and the baseplate are axially connected, the means forconstraining relative motion indirectly connects the anchor member andthe baseplate.
 17. The glenoid implant of claim 16, wherein the meansfor constraining relative motion comprises a member connecting the firstengaging surface and the second engaging surface.
 18. The glenoidimplant of claim 17, wherein the member is elastically deformable. 19.The glenoid implant of claim 9, wherein the distal portion of thebaseplate comprises a first aperture sized to accept the proximal headof the anchor member.
 20. The glenoid implant of claim 9, furthercomprising a perimeter anchor configured to secure the baseplate to thebone.
 21. The glenoid implant of claim 9, further comprising a lockingmember configured to prevent rotation between the anchor member and thebaseplate.
 22. The glenoid implant of claim 9, wherein the distalportion of the baseplate comprises a porous metal.
 23. The glenoidimplant of claim 22, wherein the porous metal is formed by additivemanufacturing.
 24. The glenoid implant of claim 9, wherein the baseplatecomprises a bone engaging surface, the bone engaging surface isasymmetric relative to a longitudinal axis of the baseplate.
 25. Theglenoid implant of claim 9, wherein the longitudinal portion of theanchor member is threadless.
 26. A glenoid implant for a shoulderprosthesis comprising: a baseplate comprising a proximal end, a distalend, an outer periphery, and an aperture that extends therethroughadjacent to the outer periphery from the proximal end to a bone engagingsurface; a screw configured to be placed through the aperture, the screwhaving an external threaded surface; and an internal member disposed inthe baseplate comprising an internal threaded surface surrounding theaperture, the internal member configured aim the screw towards a desiredlocation.
 27. The glenoid implant of claim 26, wherein the threads ofthe external threaded surface of the screw have a constant thread formalong the length thereof.
 28. The glenoid implant of claim 26, wherein afirst number of thread starts disposed on the internal threaded surfaceof the internal member is greater than a second number of thread startsdisposed on the external threaded surface of the screw.
 29. The glenoidimplant of claim 28, wherein the first number of thread starts on theinternal threaded surface of the internal member is two times the numberof second thread starts on the external threaded surface of the screw.30. The glenoid implant of claim 26, wherein the screw comprises adistal portion extending distally from the distal end of the baseplateand a proximal portion surrounded by the internal member when the screwis fully advanced, the proximal portion having the same thread pitch asthe distal portion and having a larger diameter than the distal portion.31. The glenoid implant of claim 26, wherein the internal member issemi-spherical.